1. Field
The embodiments relate to a touch panel using a light sensing method, a method for detecting a touch location, and a recording medium storing a program to execute the method.
2. Description of the Related Art
Touch panels are devices in which a user inputs operation commands by touching a panel directly. Recently, the touch panel has been used for various devices. Various methods such as a resistive method, a capacitive method, and a light sensing method are used for detecting a touch location on a touch panel.
A touch panel using the light sensing method includes light sensing circuits in a display panel. A touch location is calculated by using light sensing data generated by the light sensing circuits. The light sensing data may be values of currents generated by the light sensing circuit. The light sensing circuits are formed in a matrix format on the display panel. The currents generated by the light sensing circuits arranged in rows of the matrix format are sequentially output. The output currents are converted into digital values and stored in a line memory.
FIG. 1A is a schematic diagram illustrating a line memory of a touch panel using a light sensing method in which touch data is generated with a 1:1 method. In the 1:1 method, a touch data is generated from a value of a current generated from a single light sensing circuit. The touch data generated by using light sensing data is represented by digital data. In a touch panel having a plurality of light sensing circuits arranged in a matrix of n×m, each of m light sensing data is generated from a single scan line, and n×m light sensing data are generated during a single cycle. Therefore, n×m touch data are generated.
To this end, when the touch data is generated by using the light sensing data output from the light sensing circuits located in a first row, the touch data generated from the light sensing data output from the light sensing circuits in the first row are stored in a first line memory block. The touch data generated from the light sensing data output from the light sensing circuits in a second row are stored in a second line memory block and so forth. Thus, according to the above method, n×m light sensing data is converted into n×m digital touch data.
However, sensitivities of the light sensing circuits may not be reliable yet. When touch data is generated with the 1:1 method, accurate touch data may not be generated, and therefore, calculation of a touch location may be inaccurate.
FIG. 1B is a schematic diagram illustrating a line memory of a touch panel using the light sensing method in which touch data is generated with a 2:1 method. In the 2:1 method, a touch data is generated by using light sensing data generated by two neighboring light sensing circuits. That is, in a touch panel having a plurality of light sensing circuits arranged in a matrix of n×m, m/2 light sensing data are generated by a single scan line. Accordingly, (n×m)/2 light sensing data are generated during a single cycle, and thus, (n×m)/2 touch data are generated.
To this end, when the touch data is generated by using the light sensing data output from the light sensing circuits located in a first row, the touch data generated by the light sensing data output from the light sensing circuits in the first and second rows are stored in a first line memory block. The touch data generated from the light sensing data output from the light sensing circuits in third and fourth rows are stored in a second line memory block. Thus, according to the above method, the n×m light sensing data are converted into (n×m)/2 digital touch data.
Since more accurate touch data is generated in using the 2:1 method than the 1:1 method, calculation of a touch location may be more accurate. However, since two light sensing data generated by the two light sensing circuits are combined and converted into a touch data, the total number of touch data is reduced. Consequently, the resolution of a touch panel decreases.